The National Research Institute of Mechanical Engineering plans to organize the Institute-level Doctoral Thesis Evaluation Council for doctoral candidate Mai Tất Lợi in early July 2026. The Institute posts the information of the doctoral thesis as follows:

Full name of the doctoral candidate: Mai Tất Lợi

Scientific advisors: Prof. Dr. Vũ Ngọc Pi and Assoc. Prof. Dr. Lê Thu Quý

Major: Mechanical Engineering - Code: 9520103

Training institution: National Research Institute of Mechanical Engineering - Ministry of Industry and Trade

Thesis title: “Research on machining of external cylindrical surface by electrical discharge machining with ultrasonic vibration assistance using graphite electrode”

Summary of new findings of the thesis

1. Scientific significance

•  The research introduced ultrasonic vibration into the EDM process of the outer cylindrical surface of hardened 90CrSi material using graphite electrode. Thereby, it clarified the influence of vibration on the EDM process and determined the optimal vibration parameters and input parameters to improve the efficiency of the EDM process.
• The research will contribute some results to the research direction on vibration-assisted EDM.
• The results of the research can be used as a basis for reference for scientific studies in the field of mechanical machining.
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2. Practical significance

•    Application of ultrasonic vibration to the EDM process of outer cylindrical surfaces to enhance the efficiency of the EDM process in the practical machining of forming tablet press punches.
• The research results can serve as reference material for teaching and research in the field of mechanical machining.
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3. New contributions of the thesis

The new contributions of the thesis include:

- One of the pioneering studies on ultrasonic vibration-assisted electrical discharge machining (UV-EDM) for machining external cylindrical surfaces - a characteristic profile that is difficult to machine by traditional EDM due to debris accumulation and arc instability.

- Use of graphite electrode, a material with good electrical conductivity and high formability but susceptible to wear, thus very suitable for evaluating the effectiveness of ultrasonic vibration in reducing EWR.

- The research proposed and solved the single-objective and multi-objective optimization problem of important output indicators, including material removal rate, surface roughness, and electrode wear rate, contributing to improving the efficiency and quality of the machining process in modern manufacturing.

Based on a rigorous theoretical foundation, the clear identification of research gaps and specific practical application directions, the research promises to make important contributions to the development of UV-EDM technology in the context of Vietnam, while opening up new research and application directions in the field of advanced machining.

View detailed content of the doctoral thesis of candidate Mai Tất Lợi here